Question 41075
Find all the real and complex zeros of the polynomial x^4+4x^3-4x^2-36x-45

The polynomial facors as (x-3)(x+3)(x^2+4x+5)
The zeroes are 3, -3 and the zeroes of x^2+4x+5 which are 
worked out below:
*[invoke quadratic "x",1,4,5]
Hope this helps.
Cheers,
Stan H.